<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <title>多级菜单示例</title>
    <style>
        ul {
            list-style-type: none;
            padding-left: 20px;
        }
        li {
            margin: 5px 0;
        }
        a {
            text-decoration: none;
            color: blue;
        }
    </style>
</head>
<body>

<h2>多级菜单栏</h2>

<ul id="menu"></ul>

<script src="menu.js"></script>

</body>
</html>